G.A. Verkerk

article

Amino acid concentrations in uterine fluid during early pregnancy differ in fertile and subfertile dairy cow strains

S. Meier, M.D. Mitchell, C.G. Walker, J.R. Roche, more

Journal of Dairy Science > 2014 > 97 > 3 > 1364-1376

The objective of this study was to determine if free AA concentrations in uterine luminal fluid (ULF) and plasma differed between dairy cow strains that differ phenotypically for fertility and to evaluate the effect of the presence of a conceptus on ULF AA concentrations. Uterine luminal fluid was obtained postmortem from cows characterized on the basis of genetic ancestry as fertile (n=11) or subfertile...

article

Applying additive logistic regression to data derived from sensors monitoring behavioral and physiological characteristics of dairy cows to detect lameness

C. Kamphuis, E. Frank, J.K. Burke, G.A. Verkerk, more

Journal of Dairy Science > 2013 > 96 > 11 > 7043-7053

The hypothesis was that sensors currently available on farm that monitor behavioral and physiological characteristics have potential for the detection of lameness in dairy cows. This was tested by applying additive logistic regression to variables derived from sensor data. Data were collected between November 2010 and June 2012 on 5 commercial pasture-based dairy farms. Sensor data from weigh scales...

article

Calving body condition score affects indicators of health in grazing dairy cows

J.R. Roche, K.A. Macdonald, K.E. Schütz, L.R. Matthews, more

Journal of Dairy Science > 2013 > 96 > 9 > 5811-5825

The objectives of this study were to determine the effect of calving body condition score (BCS) on cow health during the transition period in a pasture-based dairying system. Feed inputs were managed during the second half of the previous lactation so that BCS differed at drying off (BCS 5.0, 4.0, and 3.0 for high, medium, and low treatments, respectively: a 10-point scale); feed allowance was managed...

article

Behavioral and physiological effects of a short-term feed restriction in lactating dairy cattle with different body condition scores at calving

K.E. Schütz, N.R. Cox, K.A. Macdonald, J.R. Roche, more

Journal of Dairy Science > 2013 > 96 > 7 > 4465-4476

Body condition score (BCS) around calving, and the typical BCS loss for up to 100 d after parturition, is associated with both production and reproductive performance of dairy cattle. In addition, there is public concern that thin cows may have impaired welfare, particularly in early lactation where feed demand exceeds pasture growth, and a lag exists between peak milk energy requirements and intake...

article

Noninvasive assessment of autonomic activity for evaluation of pain in calves, using surgical castration as a model

M. Stewart, G.A. Verkerk, K.J. Stafford, A.L. Schaefer, more

Journal of Dairy Science > 2010 > 93 > 8 > 3602-3609

The role of the autonomic nervous system (ANS) in mediating eye temperature responses during painful procedures was examined in thirty 4-mo-old bull calves randomly assigned to 4 treatments: 1) sham handling control (C; n=8), 2) surgical castration (SC; n=6), 3) local anesthesia with sham handling (LAC; n=8), and 4) local anesthesia with surgical castration (LASC; n=8). Maximum eye temperature (°C),...

article

Comparing subpopulations of plasma progesterone using cluster analyses

S. Meier, J.R. Roche, E.S. Kolver, G.A. Verkerk, more

Journal of Dairy Science > 2009 > 92 > 4 > 1460-1468

The production of progesterone during the luteal phase of the estrous cycle regulates early embryonic development, uterine function, and luteal function. Plasma progesterone concentrations were measured during a spontaneous estrous cycle in lactating Holstein-Friesian cows of New Zealand or North American ancestry, fed either fresh pasture or a total mixed ration. Subpopulations of profiles were identified...

article

Effects of local anesthetic and a nonsteroidal antiinflammatory drug on pain responses of dairy calves to hot-iron dehorning

M. Stewart, J.M. Stookey, K.J. Stafford, C.B. Tucker, more

Journal of Dairy Science > 2009 > 92 > 4 > 1512-1519

This study examined the effects of a nonsteroidal antiinflammatory agent (NSAID) on physiological responses of calves immediately after hot-iron dehorning (DH) and during the time that local anesthetic (LA) wears off (2 to 3h) after this procedure. Forty-six calves (33±0.3 d of age) were randomly assigned to 6 treatments: hot-iron DH versus sham DH with either no pain mitigation, LA alone, or LA with...

article

Somatotropic axis components and nutrient partitioning in genetically diverse dairy cows managed under different feed allowances in a pasture system

M.C. Lucy, G.A. Verkerk, B.E. Whyte, K.A. Macdonald, more

Journal of Dairy Science > 2009 > 92 > 2 > 526-539

The somatotropic axis [including growth hormone (GH), GH receptor, and insulin-like growth factor (IGF)-I] is uncoupled in high-producing cows in early lactation so that the liver fails to respond to GH and produces less IGF-I. This uncoupling was implicated in the process of nutrient partitioning, enabling high milk production. Different genetic selection goals may affect functional components of...

article

A Comparison of Three Strains of Holstein-Friesian Grazed on Pasture and Managed Under Different Feed Allowances

K.A. Macdonald, G.A. Verkerk, B.S. Thorrold, J.E. Pryce, more

Journal of Dairy Science > 2008 > 91 > 4 > 1693-1707

This experiment compared Holstein-Friesian (HF) cows of New Zealand (NZ) origin representative of genetics present in the 1970s (NZ70; n=45) and 1990s (NZ90; n=60), and a group of HF cows of North American origin with 1990s genetics (NA90; n=60), which were managed in grazing systems with a range of feeding allowances (4.5 to 7.0 t/cow per yr) over 3 yr. The NZ70 cows had the lowest Breeding Worth...

article

Metabolic adaptations associated with irreversible glucose loss are different to those observed during under-nutrition

S. Meier, P.J.S. Gore, C.M.E. Barnett, R.T. Cursons, more

Domestic Animal Endocrinology > 2008 > 34 > 3 > 269-277

In this study the hypothesis that irreversible glucose loss results in an ‘uncoupling’ of the somatotrophic axis (increasing plasma GH levels and decreasing plasma IGF-I) was tested. During periods of negative energy balance the somatotrophic axis respond by increasing plasma GH and decreasing plasma IGF-I levels. In turn, elevated GH repartitions nutrient by increasing lipolysis and protein synthesis,...

article

Non-invasive measurement of stress in dairy cows using infrared thermography

M. Stewart, J.R. Webster, G.A. Verkerk, A.L. Schaefer, more

Physiology & Behavior > 2007 > 92 > 3 > 520-525

The possibility that changes in eye temperature, measured using infrared thermography (IRT), can detect stress in dairy cattle was examined by six different stimulations of the stress axis. Six cows were given six treatments in a random Latin-square design: 1) Control (saline) 2) ACTH (0.05 mg Synacthen) 3) bCRH (20 μg) 4) bCRH (40 μg) 5) epinephrine (1.4 μg /kg liveweight) and 6) social isolation...

article

Sprinklers and Shade Cool Cows and Reduce Insect-Avoidance Behavior in Pasture-Based Dairy Systems

P.E. Kendall, G.A. Verkerk, J.R. Webster, C.B. Tucker

Journal of Dairy Science > 2007 > 90 > 8 > 3671-3680

The body temperature of dairy cows in pastoral systems during summer reaches a peak during and following the p.m. milking. Shade and sprinklers can be used separately or in combination at the milking parlor to reduce heat load. Farmers anecdotally report that the use of sprinklers reduces irritation from insects that occurs while cows are waiting for milking. Once daily, we assessed the effectiveness...

article

A Comparison of Three Strains of Holstein-Friesian Cows Grazed on Pasture: Growth, Development, and Puberty

K.A. Macdonald, L.R. McNaughton, G.A. Verkerk, J.W. Penno, more

Journal of Dairy Science > 2007 > 90 > 8 > 3993-4003

With the introduction of a protein milk payment system in New Zealand in 1988, there was an influx of North American (NA) Holstein-Friesian (HF) genetics into New Zealand (NZ) dairy herds, leading to an increase in the average percentage of NA genetics in NZ HF cows—from 2% in 1980 to 38% in 1999. Of interest has been the effect this change has had on farm profitability and on the management required...

article

Effect of Monopropylene Glycol on Luteinizing Hormone, Metabolites, and Postpartum Anovulatory Intervals in Primiparous Dairy Cows

L.M. Chagas, P.J.S. Gore, S. Meier, K.A. Macdonald, more

Journal of Dairy Science > 2007 > 90 > 3 > 1168-1175

This study examined the effect of monopropylene glycol (MPG) supplementation on LH secretion, postpartum interval to first ovulation, and milk production in heifers calving with poor body condition score (BCS). Forty-seven heifers were allocated to 3 treatments: 1) heifers with high BCS (BCH; n=13) that calved at a BCS of 3.4 (BCS scale of 1 to 5); 2) heifers with low BCS (BCL; n=17) that calved at...

article

The effects of providing shade to lactating dairy cows in a temperate climate

P.E. Kendall, P.P. Nielsen, J.R. Webster, G.A. Verkerk, more

Livestock Science > 2006 > 103 > 1-2 > 148-157

In a two-period replicated crossover design, four groups of lactating Holstein Friesian dairy cows (n=10 per group) were kept on pasture to investigate the effects of providing artificial shade in summer on their vaginal temperature, behaviour and milk production. Two groups had access to shade and two groups in adjacent paddocks had no shade for a 10-day period before the treatments were switched...

article

Precalving Effects on Metabolic Responses and Postpartum Anestrus in Grazing Primiparous Dairy Cows

L.M. Chagas, F.M. Rhodes, D. Blache, P.J.S. Gore, more

Journal of Dairy Science > 2006 > 89 > 6 > 1981-1989

The effect of increased access to pasture feeding during the last 6 wk of gestation on metabolic responses and postpartum anestrous interval was investigated. Heifers with a body condition score (BCS) of 5.0 (BC5+FF; on a 1-to-10 scale, US=1.5+0.32×New Zealand) were offered unrestricted pasture, and those with BCS 4.0 were fed either pasture unrestricted (BC4+FF) or restricted (BC4+RES) for the last...

article

Can female-female stimulation of breeding condition occur in dairy goats?

N. Hogan, J.R. Waas, G.A. Verkerk

Small Ruminant Research > 2004 > 55 > 1-3 > 21-27

The social stimulation of oestrus by oestrous females (i.e., the 'female-female effect') was investigated in dairy goats under typical pasture-grazing conditions in New Zealand. Five anoestrous does were grouped with either one doe treated with hormones to induce oestrus (n=10 groups), or one doe which received a sham hormone treatment (n=10 groups). The occurrence and frequency of three activities...

article

Invited Review: Treatment of Cows with an Extended Postpartum Anestrous Interval

F.M. Rhodes, S. McDougall, C.R. Burke, G.A. Verkerk, more

Journal of Dairy Science > 2003 > 86 > 6 > 1876-1894

Cows with an extended interval from calving to first ovulation (PPI) have increased intervals from calving to conception and are more likely to be culled compared with cows with a short PPI. In year-round calving dairy herds, between 11 and 38% of cows are reported as anestrus by 50 or 60 d after calving. In seasonally calving dairy herds, between 13 and 48% of cows are diagnosed as anovulatory anestrus...

article

The effects of surface type on lying behaviour and stress responses of dairy cows during periodic weather-induced removal from pasture

A.D. Fisher, M. Stewart, G.A. Verkerk, C.J. Morrow, more

Applied Animal Behaviour Science > 2003 > 81 > 1 > 1-11

In some dairy cow grazing systems, during wet weather, the cows are removed from the pasture to a separate area for most of the day, in order to minimise treading damage to the soil. The objective of this study was to compare the effects of four surfaces commonly used for this ''stand-off'' procedure, in terms of cow lying behaviour, bodyweight, dirtiness, locomotion, and faecal concentrations of...

article

The effects of feed restriction and lying deprivation on pituitary-adrenal axis regulation in lactating cows

A.D. Fisher, G.A. Verkerk, C.J. Morrow, L.R. Matthews

Livestock Production Science > 2002 > 73 > 2-3 > 255-263

In order to examine the effects of moderate feed restriction and periodic lying deprivation on pituitary-adrenal axis function in lactating dairy cows, 32 non-pregnant Jersey cows were allocated to two levels of feeding (4% vs. 3% of body weight of dry matter daily) and lying restriction (free lying vs. prevention of lying from 15:00 to 06:45 h daily) in a 2x2 factorial plan for 7 days. There were...

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Search results for: G.A. Verkerk

Amino acid concentrations in uterine fluid during early pregnancy differ in fertile and subfertile dairy cow strains

Applying additive logistic regression to data derived from sensors monitoring behavioral and physiological characteristics of dairy cows to detect lameness

Calving body condition score affects indicators of health in grazing dairy cows

Behavioral and physiological effects of a short-term feed restriction in lactating dairy cattle with different body condition scores at calving

Noninvasive assessment of autonomic activity for evaluation of pain in calves, using surgical castration as a model

Comparing subpopulations of plasma progesterone using cluster analyses

Effects of local anesthetic and a nonsteroidal antiinflammatory drug on pain responses of dairy calves to hot-iron dehorning

Somatotropic axis components and nutrient partitioning in genetically diverse dairy cows managed under different feed allowances in a pasture system

A Comparison of Three Strains of Holstein-Friesian Grazed on Pasture and Managed Under Different Feed Allowances

Metabolic adaptations associated with irreversible glucose loss are different to those observed during under-nutrition

Non-invasive measurement of stress in dairy cows using infrared thermography

Sprinklers and Shade Cool Cows and Reduce Insect-Avoidance Behavior in Pasture-Based Dairy Systems

A Comparison of Three Strains of Holstein-Friesian Cows Grazed on Pasture: Growth, Development, and Puberty

Effect of Monopropylene Glycol on Luteinizing Hormone, Metabolites, and Postpartum Anovulatory Intervals in Primiparous Dairy Cows

The effects of providing shade to lactating dairy cows in a temperate climate

Precalving Effects on Metabolic Responses and Postpartum Anestrus in Grazing Primiparous Dairy Cows

Can female-female stimulation of breeding condition occur in dairy goats?

Invited Review: Treatment of Cows with an Extended Postpartum Anestrous Interval

The effects of surface type on lying behaviour and stress responses of dairy cows during periodic weather-induced removal from pasture

The effects of feed restriction and lying deprivation on pituitary-adrenal axis regulation in lactating cows

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